From ce13a2a7bc50d2c23678806acf65dbd589827c77 Mon Sep 17 00:00:00 2001
From: chenrui <chenrui@jingdaka.com>
Date: Mon, 7 Mar 2022 14:39:56 +0800
Subject: [PATCH] fix: soft delete for join.on

---
 callbacks/query.go  | 13 ++++++++++++-
 soft_delete.go      | 18 ++++++++++++++++++
 statement.go        |  7 +++++++
 tests/joins_test.go | 23 +++++++++++++++++++++++
 4 files changed, 60 insertions(+), 1 deletion(-)

diff --git a/callbacks/query.go b/callbacks/query.go
index 03798859..2c61d6c7 100644
--- a/callbacks/query.go
+++ b/callbacks/query.go
@@ -107,6 +107,7 @@ func BuildQuerySQL(db *gorm.DB) {
 				}
 			}
 
+			joinQueryClauses := make([]clause.Interface, 0)
 			for _, join := range db.Statement.Joins {
 				if db.Statement.Schema == nil {
 					joins = append(joins, clause.Join{
@@ -160,6 +161,10 @@ func BuildQuerySQL(db *gorm.DB) {
 						exprs = append(exprs, clause.Expr{SQL: onSQL, Vars: vars})
 					}
 
+					if len(relation.FieldSchema.QueryClauses) > 0 {
+						joinQueryClauses = append(joinQueryClauses, relation.FieldSchema.QueryClauses...)
+					}
+
 					joins = append(joins, clause.Join{
 						Type:  clause.LeftJoin,
 						Table: clause.Table{Name: relation.FieldSchema.Table, Alias: tableAliasName},
@@ -172,8 +177,14 @@ func BuildQuerySQL(db *gorm.DB) {
 				}
 			}
 
-			db.Statement.Joins = nil
 			db.Statement.AddClause(clause.From{Joins: joins})
+
+			if len(joinQueryClauses) > 0 {
+				for _, c := range joinQueryClauses {
+					db.Statement.UpdateModifierJoinClause(c)
+				}
+			}
+			db.Statement.Joins = nil
 		} else {
 			db.Statement.AddClauseIfNotExists(clause.From{})
 		}
diff --git a/soft_delete.go b/soft_delete.go
index 6d646288..9b5982b1 100644
--- a/soft_delete.go
+++ b/soft_delete.go
@@ -82,6 +82,24 @@ func (sd SoftDeleteQueryClause) ModifyStatement(stmt *Statement) {
 		}})
 		stmt.Clauses["soft_delete_enabled"] = clause.Clause{}
 	}
+
+	// Modify for Joins[i].ON exprs
+	if _, ok := stmt.Clauses["soft_delete_join_enabled"]; !ok && !stmt.Statement.Unscoped {
+		if c, ok := stmt.Clauses["FROM"]; ok && len(stmt.Joins) > 0 {
+			if fromClause, ok := c.Expression.(clause.From); ok && len(fromClause.Joins) > 0 {
+				for i, j := range fromClause.Joins {
+					if sd.Field.Schema != nil && j.Table.Name == sd.Field.Schema.Table {
+						j.ON.Exprs = append(j.ON.Exprs, clause.Eq{
+							Column: clause.Column{Table: j.Table.Alias, Name: sd.Field.DBName}, Value: nil,
+						})
+					}
+					fromClause.Joins[i] = j
+				}
+			}
+			stmt.Clauses["FROM"] = c
+			stmt.Clauses["soft_delete_join_enabled"] = clause.Clause{}
+		}
+	}
 }
 
 func (DeletedAt) UpdateClauses(f *schema.Field) []clause.Interface {
diff --git a/statement.go b/statement.go
index cb471776..ed5635bd 100644
--- a/statement.go
+++ b/statement.go
@@ -271,6 +271,13 @@ func (stmt *Statement) AddClauseIfNotExists(v clause.Interface) {
 	}
 }
 
+// UpdateModifierJoinClause update join clause for modifier
+func (stmt *Statement) UpdateModifierJoinClause(v clause.Interface) {
+	if optimizer, ok := v.(StatementModifier); ok {
+		optimizer.ModifyStatement(stmt)
+	}
+}
+
 // BuildCondition build condition
 func (stmt *Statement) BuildCondition(query interface{}, args ...interface{}) []clause.Expression {
 	if s, ok := query.(string); ok {
diff --git a/tests/joins_test.go b/tests/joins_test.go
index 4c9cffae..f9d66649 100644
--- a/tests/joins_test.go
+++ b/tests/joins_test.go
@@ -200,3 +200,26 @@ func TestJoinCount(t *testing.T) {
 		t.Fatalf("result's id, %d, doesn't match user's id, %d", result.ID, user.ID)
 	}
 }
+
+// https://github.com/go-gorm/gorm/issues/4918
+func TestJoinWithSoftDeleted(t *testing.T) {
+	user := User{Name: "TestJoinWithSoftDeleted"}
+	DB.Create(&user)
+
+	pet := Pet{Name: "A", UserID: &user.ID}
+	DB.Create(&pet)
+
+	DB = DB.Debug()
+
+	var user1 User
+	DB.Debug().Model(&User{}).Joins("NamedPet").First(&user1, user.ID)
+	AssertEqual(t, user1.ID, user.ID)
+	AssertEqual(t, user1.NamedPet.ID, pet.ID)
+
+	DB.Delete(&pet)
+
+	var user3 User
+	DB.Model(&User{}).Joins("NamedPet").First(&user3, user.ID)
+	AssertEqual(t, user3.ID, user.ID)
+	AssertEqual(t, user3.NamedPet, nil) // soft deleted for join.on
+}